US6111765A - Discharge lamp operating circuit using piezoelectric transformer and protective device - Google Patents

Discharge lamp operating circuit using piezoelectric transformer and protective device Download PDF

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Publication number
US6111765A
US6111765A US09/140,812 US14081298A US6111765A US 6111765 A US6111765 A US 6111765A US 14081298 A US14081298 A US 14081298A US 6111765 A US6111765 A US 6111765A
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US
United States
Prior art keywords
inverter
circuit
lamp
coupled
terminals
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US09/140,812
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English (en)
Inventor
Hans G. Ganser
Dieter Leers
Klaus Lohn
Martin Ossmann
Pieter Postma
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US Philips Corp
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US Philips Corp
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Assigned to U.S. PHILIPS CORPORATION reassignment U.S. PHILIPS CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: POSTMA, PIETER, OSSMANN, MARTIN, LOHN, KLAUS, LEERS, DIETER, GANSER, HANS GUNTER
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Publication of US6111765A publication Critical patent/US6111765A/en
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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2851—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • H05B41/2856—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against internal abnormal circuit conditions
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
    • H05B41/2881—Load circuits; Control thereof
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/382—Controlling the intensity of light during the transitional start-up phase
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S323/00—Electricity: power supply or regulation systems
    • Y10S323/901—Starting circuits

Definitions

  • This invention relates to a circuit arrangement for operating a lamp comprising
  • circuit input terminals for connection to a supply voltage source, an inverter coupled to said circuit input terminals for generating an AC voltage with a frequency f from a supply voltage supplied by the supply voltage source and equipped with inverter output terminals,
  • a piezotransformer comprising transformer input terminals, coupled to the inverter output terminals, and transformer output terminals,
  • a detector for detecting whether the lamp has ignited.
  • Such a circuit arrangement is known from Jp H6-89789.
  • the known circuit arrangement is very suitable for operating a discharge lamp and comprises a switching circuit part that connects the inverter output to the transformer input during the ignition of the lamp.
  • the lamp is directly connected to the transformer output terminals.
  • the frequency f of the AC voltage generated by the inverter is very close to one of the resonance frequencies of the piezotransformer. Therefore the AC voltage is transformed by the piezotransformer to an ignition voltage with the same frequency f but a much higher amplitude that is present across the lamp.
  • the detector which is part of the circuit arrangement, detects a lamp current and generates a signal that triggers the switching circuit part to disconnect the inverter output and the transformer input.
  • the piezotransformer no longer generates the ignition voltage and the lamp is operated by means of the AC voltage at the frequency f that is generated by the inverter.
  • An important advantage of the known circuit arrangement is that the inverter is used both in the generation of the voltage that is used to operate the lamp during stationary conditions as well as in the generation of the ignition voltage. For this reason the known circuit arrangement comprises a relatively small amount of components and is therefore relatively inexpensive and compact.
  • a disadvantage of the known circuit arrangement is that during ignition the high ignition voltage is present between the output terminals. This can easily lead to damage to the inverter.
  • the invention aims to provide a circuit arrangement for operating a lamp in which a separate oscillator for driving the piezotransformer can be dispensed with and in which the inverter can not be damaged by the ignition of the lamp.
  • a circuit arrangement as described in the opening paragraph is therefore characterized in that the circuit arrangement is equipped with a protective device coupled between the output terminals of the inverter and the transformer output terminals.
  • the protective device assures that the voltage that is present between the output terminals of the inverter during ignition of the lamp has a lower amplitude than the voltage that is present between the output terminals of the piezotransformer, and thereby prevents damage to the inverter.
  • the protective device comprises a switching element and control circuitry coupled to the detector for controlling the switching element into a non-conductive state during ignition and into a conductive state after ignition.
  • a circuit arrangement according to the invention preferably comprises a frequency control circuit coupled to the detector for changing the frequency f after ignition.
  • the frequency control circuit changes the frequency from a first fixed value before ignition to a second fixed value after ignition.
  • the detector may comprise a current sensor that directly or indirectly measures a current through the lamp. In this way the detector is realized in a relatively simple and effective way.
  • a relatively simple and inexpensive embodiment of a circuit arrangement according to the invention is obtained when the transformer input terminals are connected directly to the inverter output terminals.
  • FIG. 1 shows a schematic representation of a first embodiment of a circuit arrangement according to the invention with a lamp connected to it
  • FIG. 2 shows a schematic representation of a second embodiment of a circuit arrangement according to the invention with a lamp connected to it.
  • K1 and K2 are circuit input terminals for connection to a supply voltage source.
  • K1 and K2 are connected to respective input terminals of rectifier bridge RB.
  • Output terminals of rectifier bridge RB are connected by means of a capacitor C1 functioning as a buffer capacitor.
  • One end of capacitor C1 is connected to ground potential.
  • Respective ends of capacitor C1 are connected to input terminals of a DC-DC-converter DDC comprising inductive means, unidirectional means and at least one switching element.
  • a control electrode of the switching element is connected to a first control circuit CC1 for generating a control signal for rendering the switching element conductive and non-conductive at a high frequency. This connection is represented schematically in FIG.
  • the second control circuit CCII comprises a circuit part I. Circuit part I forms the means for changing the frequency f in response to the ignition of the lamp. For this purpose circuit part I is coupled to resistor R. This coupling is indicated by means of a dotted line.
  • K3 and K4 are inverter output terminals.
  • K5 and K6 are input terminals of piezotransformer PT.
  • K7 and K8 are terminals for lamp connection.
  • Output terminal K3 is connected to input terminal K5 and output terminal K4 is connected to both input terminal K6 and lamp connection terminal K8 via ohmic resistor R.
  • Input terminal K5 is connected to terminal K7 for lamp connection by means of a choke L. Input terminal K5 is also connected to ground potential by means of capacitor C2. Choke L and capacitor C2 together form a filter that acts as a protective device in this embodiment. Ohmic resistor R forms a detector for detecting whether the lamp has ignited. Output terminal K9 of piezotransformer PT is connected to lamp connection terminal K7. In the embodiment shown in FIG. 1, K6 forms another output terminal of piezotransformer PT.
  • a high pressure discharge lamp La comprising electrodes E11 and E12 is connected to the terminals for lamp connection.
  • the low frequency AC supply voltage is rectified by means of the rectifier bridge RB, so that a DC voltage is present on capacitor C1.
  • the first control circuit CCI renders the switching element comprised in the DC-DC-converter DDC conducting and non-conducting at a high frequency.
  • the DC voltage present across capacitor C1 is converted by means of DC-DC-converter DDC into a substantially constant DC voltage present between the input terminals of the full bridge circuit.
  • the second control circuit CCII renders on the one hand switching elements S1 and S4 and on the other hand switching elements S2 and S3 alternately conducting and non-conducting at a frequency f.
  • the full bridge circuit Out of the substantially constant DC voltage that is present between its input terminals, the full bridge circuit generates a substantially square wave shaped AC voltage at a frequency f that is present between the inverter output terminals K3 and K4. This substantially square wave shaped AC voltage is also present between the transformer input terminals K5 and K6.
  • the frequency f is chosen so that it is very close to one of the resonance frequencies of the piezotransformer PT.
  • the piezotransformer transforms the substantially square wave shaped AC voltage with frequency f to a sinusoidal ignition voltage with frequency f and a relatively high amplitude that is present between transformer output terminals K6 and K9 and between terminals K7 and K8 for lamp connection.
  • the filter that is formed by choke L and capacitor C2 protects the full bridge circuit against the ignition voltage present across the lamp La.
  • the lamp and also the resistor R start conducting a current.
  • the circuit part I included in the second control circuit CCII changes the frequency f at which the switching elements comprised in the full bridge circuit are rendered conducting and non-conducting to a value that corresponds to the stationary operation of the lamp.
  • the frequency f is changed to a value that differs substantially from all the resonance frequencies of the piezotransformer so that at that frequency its voltage transformation ratio is very low and the voltage across the lamp is therefore almost completely determined by the inverter.
  • the configuration of the circuit arrangement shown in FIG. 2 is very similar to the configuration of the circuit arrangement shown in FIG. 1. Circuit parts and components of the circuit arrangement shown in FIG. 2 that are similar to circuit parts and components in the circuit arrangement shown in FIG. 1 are indicated with the same reference symbol.
  • the filter that is formed by choke L and capacitor C2 in the circuit arrangement shown in FIG. 1 is replaced by a switching element that has a first main electrode connected to terminal K5 and a second main electrode connected to terminal K7 and K9.
  • a control electrode of the switching element is connected to an output terminal of second control circuit CCII.
  • Second control circuit CCII is equipped with control circuitry (not shown in the figure) for controlling the switching element into a non-conductive state during ignition and into a conductive state after ignition.

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)
US09/140,812 1997-09-01 1998-08-26 Discharge lamp operating circuit using piezoelectric transformer and protective device Expired - Fee Related US6111765A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP97202685 1997-09-01
EP97202685 1997-09-01
EP98202101 1998-06-24
EP98202101 1998-06-24

Publications (1)

Publication Number Publication Date
US6111765A true US6111765A (en) 2000-08-29

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US09/140,812 Expired - Fee Related US6111765A (en) 1997-09-01 1998-08-26 Discharge lamp operating circuit using piezoelectric transformer and protective device

Country Status (5)

Country Link
US (1) US6111765A (de)
EP (1) EP0948876A2 (de)
JP (1) JP2001504987A (de)
CN (1) CN1237320A (de)
WO (1) WO1999012390A2 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030099071A1 (en) * 2001-10-20 2003-05-29 Joerg Reineke Circuit system for discharging a buffer capacitor used for supplying high voltage to a control unit, in particular a control unit for actuating a piezoelectric output stage
US20030137260A1 (en) * 2002-01-18 2003-07-24 Mitsubishi Denki Kabushiki Kaisha Discharge lamp lighting device
US20040135555A1 (en) * 2002-10-29 2004-07-15 Stmicroelectronics S.R.L. Device for driving a power transistor of a voltage converter provided with a piezoelectric transformer and corresponding voltage converter
US20050062433A1 (en) * 2003-08-11 2005-03-24 Andrea Ongaro Power supply system for liquid crystal monitors
US6894616B1 (en) * 1999-07-29 2005-05-17 Mineral Lassen Llc Piezo-electric tag
EP1679943A1 (de) * 2004-12-28 2006-07-12 Media Technology Inc. Vorschaltgerät für eine Hochspannungsentladungslampe

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1016078C2 (nl) * 2000-09-01 2002-03-05 Vmi Epe Holland Lasinrichting voor het aan elkaar lassen van stroken van in rubbermateriaal ingebedde koorden.

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5548189A (en) * 1992-03-26 1996-08-20 Linear Technology Corp. Fluorescent-lamp excitation circuit using a piezoelectric acoustic transformer and methods for using same
US5705877A (en) * 1995-10-12 1998-01-06 Nec Corporation Piezoelectric transformer driving circuit
US5731652A (en) * 1995-03-08 1998-03-24 Nec Corporation Power source unit employing piezoelectric transformer frequency-controlled and voltage-controlled to operate at a maximum efficiency
US5739679A (en) * 1995-09-04 1998-04-14 Minebea Co., Ltd. Cold cathode tube lighting device using piezoelectric transformer
US5760619A (en) * 1995-08-30 1998-06-02 Nec Corporation Piezoelectric transformer driver circuit
US5834907A (en) * 1994-11-16 1998-11-10 Minebea Co., Ltd. Cold cathode tube operating apparatus with piezoelectric transformer
US5894184A (en) * 1996-08-01 1999-04-13 Nec Corporation Drive circuit for driving a piezoelectric transformer capable of decreasing heat developed from electronic parts composing an inverter circuit

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0689789A (ja) * 1992-09-07 1994-03-29 Toto Ltd 放電灯点灯装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5548189A (en) * 1992-03-26 1996-08-20 Linear Technology Corp. Fluorescent-lamp excitation circuit using a piezoelectric acoustic transformer and methods for using same
US5834907A (en) * 1994-11-16 1998-11-10 Minebea Co., Ltd. Cold cathode tube operating apparatus with piezoelectric transformer
US5731652A (en) * 1995-03-08 1998-03-24 Nec Corporation Power source unit employing piezoelectric transformer frequency-controlled and voltage-controlled to operate at a maximum efficiency
US5760619A (en) * 1995-08-30 1998-06-02 Nec Corporation Piezoelectric transformer driver circuit
US5739679A (en) * 1995-09-04 1998-04-14 Minebea Co., Ltd. Cold cathode tube lighting device using piezoelectric transformer
US5705877A (en) * 1995-10-12 1998-01-06 Nec Corporation Piezoelectric transformer driving circuit
US5894184A (en) * 1996-08-01 1999-04-13 Nec Corporation Drive circuit for driving a piezoelectric transformer capable of decreasing heat developed from electronic parts composing an inverter circuit

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6894616B1 (en) * 1999-07-29 2005-05-17 Mineral Lassen Llc Piezo-electric tag
USRE42449E1 (en) 1999-07-29 2011-06-14 Mineral Lassen Llc Piezo-electric tag
US20030099071A1 (en) * 2001-10-20 2003-05-29 Joerg Reineke Circuit system for discharging a buffer capacitor used for supplying high voltage to a control unit, in particular a control unit for actuating a piezoelectric output stage
US6982517B2 (en) * 2001-10-20 2006-01-03 Robert Bosch Gmbh Circuit system for discharging a buffer capacitor used for supplying high voltage to a control unit, in particular a control unit for actuating a piezoelectric output stage
US20030137260A1 (en) * 2002-01-18 2003-07-24 Mitsubishi Denki Kabushiki Kaisha Discharge lamp lighting device
US6781327B2 (en) * 2002-01-18 2004-08-24 Mitsubishi Denki Kabushiki Kaisha Discharge lamp lighting device
US20040135555A1 (en) * 2002-10-29 2004-07-15 Stmicroelectronics S.R.L. Device for driving a power transistor of a voltage converter provided with a piezoelectric transformer and corresponding voltage converter
US6885172B2 (en) * 2002-10-29 2005-04-26 Stmicroelectronics S.R.L. Device for driving a power transistor of a voltage converter provided with a piezoelectric transformer and corresponding voltage converter
US20050062433A1 (en) * 2003-08-11 2005-03-24 Andrea Ongaro Power supply system for liquid crystal monitors
US7233113B2 (en) * 2003-08-11 2007-06-19 Global Display Solutions S.P.A. Power supply system for liquid crystal monitors
EP1679943A1 (de) * 2004-12-28 2006-07-12 Media Technology Inc. Vorschaltgerät für eine Hochspannungsentladungslampe

Also Published As

Publication number Publication date
WO1999012390A2 (en) 1999-03-11
EP0948876A2 (de) 1999-10-13
WO1999012390A3 (en) 1999-05-27
JP2001504987A (ja) 2001-04-10
CN1237320A (zh) 1999-12-01

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Owner name: U.S. PHILIPS CORPORATION, NEW YORK

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GANSER, HANS GUNTER;LEERS, DIETER;LOHN, KLAUS;AND OTHERS;REEL/FRAME:009575/0231;SIGNING DATES FROM 19980929 TO 19981025

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STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

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Effective date: 20080829